编写一个shell，通过pg_stat_activity查询greenplum空进程，并调用pg_terminagte_backend进程

可以编写如下Shell脚本来查询并杀掉Greenplum的空进程：

#!/bin/bash

# 查询正在运行的Greenplum进程
pg_processes=$(psql -h <host> -p <port> -U <user> -c "SELECT pid, usename, datname, application_name, client_addr, query, state FROM pg_stat_activity WHERE state = 'idle' AND query NOT LIKE '%IDLE%' AND query NOT LIKE '%pg_stat_activity%';" -t)

if [ -z "$pg_processes" ]; then
    echo "No Greenplum idle processes running." >&2
    exit 1
fi

# 遍历进程，找到空进程并杀掉
while read -r pg_process; do
    pg_pid=$(echo "$pg_process" | awk '{ print $1 }')
    echo "Killing idle Greenplum process (PID: $pg_pid)"
    psql -h <host> -p <port> -U <user> -c "SELECT pg_terminate_backend($pg_pid)"
done <<< "$pg_processes"

这个脚本首先通过`psql`命令查询正在运行的Greenplum进程，筛选出状态为`idle`、且`query`不包含`IDLE`和`pg_stat_activity`的进程。然后遍历每一个进程，使用`psql`命令调用`pg_terminate_backend`函数杀掉进程。